Filter cartridge support

ABSTRACT

Each cap of a pair of end caps mounted on opposed ends of a conventional radial flow cylindrical filter element of a filter cartridge includes a circular sleeve extending axially from the filter element for penetrably receiving a supporting stud and for maintaining an O-ring seal therebetween. The area of one of the end caps radially outwardly of its circular sleeve is greater than the corresponding area of the other end cap to cause fluid to be filtered to pressure bias the filter cartridge toward the other end cap and to positionally retain the filter cartridge within its housing. A positioning member extending into the filter element from one of the end caps receives and stabilizes sleeve for a u/v lamp disposed within the filter element to kill any microorganisms present and to oxidize any organic matter subjected to the emitted ultra-violent radiation.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present invention claims priority to the subject matter disclosed in a provisional application entitled “EK FILTER” filed Jan. 12, 2000 and assigned Serial No. 60/175,797 directed to an invention made by the present inventors.

[0002] The present application describes apparatus related to an usable with the inventions described in U.S. Pat. No. 5,266,215 issued Nov. 30, 1993 and U.S. Pat. No. 5,540,848 issued Jul. 30, 1996, and U.S. Pat. No. 5,709,799 issued Jan. 20, 1998 which patents are assigned to the present Assignee and incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The present invention relates to mountings for filter cartridges and, more particularly, to seals for sealing opposed ends of a filter element of a filter cartridge that accommodate for axial movement of the filter cartridge without compromising the seals.

[0005] 2. Description of Related Art

[0006] Filter cartridges have been in use for decades to filter with a cylindrical filter element a fluid flowing radially therethrough. Usually, the fluid flow through the filter element is from its external surface to its internal surface. Thereafter, the fluid is exhausted axially from one end. Each opposed end of the filter element include a compressible annular cap mating with an annular knife edge of a housing. Each annular knife edge forms a seal with the respective end cap as a function of the compression therebetween imposed by the housing and the elasticity and resiliency of the filter element. Over a period of time, the end caps tend to acquire a set and the pressure against the corresponding annular knife edge diminishes to the point where the seal is compromised.

[0007] The resiliency and elasticity of the filter element providing a bias against the opposed annular knife edges diminish over a period of time or through deterioration caused at least in part by interaction with the fluid being filtered. The loss of resiliency and elasticity compromises the bias force against the opposed annular knife edges. The pressure differential on opposed sides of each annular knife edge increases as the filter element becomes more and more clogged. Such increase in pressure differential, coupled with the compromised sealing bias, will cause leakage. The resulting leakage will contaminate the previously filtered fluid with potentially disastrous results.

[0008] The previously known solution to extend the filtering life of a filter cartridge has been that of increasing the pressure bias of the annular knife edges on the opposed ends of the filter element. At best, this solution increases the life of the sealing function of the annular knife edges for a limited period of time.

[0009] Another problem with conventional filter cartridges is that tolerances of filter cartridges from different manufacturers are not the same. Thus, a presumably standard sized filter cartridge may not fit a housing for such filter cartridge sufficiently well to maintain a seal for a reasonable period of time before being affected by the above described modes of deterioration.

SUMMARY OF THE INVENTION

[0010] A housing for a filter cartridge includes a cylinder having a closed bottom for receiving the filter cartridge and a top threadedly engageable with the open end of the cylinder to close the housing. An inlet proximate to the bottom of the cylinder introduces fluid to be filtered to the exterior surface of the filter cartridge and an outlet in axial alignment with the filter cartridge extends through the top for discharge of the filtered fluid. An end cap on the filter cartridge includes a circular sleeve for receiving a stud extending inwardly from the bottom of the cylinder and an O-ring disposed therebetween serves as a seal to prevent inflow of unfiltered fluid into the axial center of the filter cartridge. A similar end cap is disposed at the other end of the filter cartridge, its circular sleeve circumscribes a hollow stud defining the outlet and an O-ring disposed between the stud and the circular sleeve prevents mixing of the filtered and unfiltered fluids. The use of the O-rings between the respective circular sleeves and studs accommodates axial translation of the filter cartridge without compromising the respective seals. By having the surface area radially external of the circular sleeve of one of the end caps greater than that of the other end cap provides a pressure bias induced by the inflowing unfiltered fluid to urge the filter cartridge in the direction of the end cap with the lesser area subject to the inflowing unfiltered fluid. Upon axially stacking two or more filter cartridges, an O-ring is placed intermediate overlapping circular sleeves of adjacent cartridges to maintain the seal at the junction of the filter cartridges to preclude mixing of the filtered and unfiltered fluids.

[0011] It is therefore a primary object of the present invention to provide seals at opposed ends of a filter cartridge that do not depend upon resiliency and elasticity of the filter element.

[0012] Another object of the present invention is to provide seals for a filter cartridge that accommodate axially translation of the filter cartridge without compromising the respective seals.

[0013] Yet another object of the present invention is to provide sealing elements at opposed ends of a filter cartridge to permit use of a single or axially stacked filter cartridges within a housing without compromising the seals necessary to prevent mixing of filtered and unfiltered fluids flowing through the housing.

[0014] A further object of the present invention is to provide a housing for a filter cartridge which does not compress the filter cartridge to establish seals to control flow of the fluid to be filtered therein.

[0015] A yet further object of the present invention is to provide an end cap for a filter cartridge which positionally maintains an ultra-violet lamp assembly in fixed position therewithin.

[0016] A still further object of the present invention is to provide an axially translatable filter cartridge disposed in sealed relationship within a housing for supporting an ultra-violet lamp assembly therewithin.

[0017] A still further object of the present invention is to bias a filter cartridge toward one end of an enclosing housing as a function of the pressure of the inflowing fluid to be filtered.

[0018] A still further object of the present invention is to provide an inexpensive filter cartridge and housing having seals not affected by deterioration of the resiliency and elasticity of the filter element.

[0019] A still further object of the present invention is to provide a method for sealing a filter cartridge within a housing.

[0020] The and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be described with greater specificity and clarity with reference to the following drawings, in which:

[0022]FIG. 1 illustrates a cross section of a conventional filter cartridge, housing and attendant seals used in the prior art;

[0023]FIG. 2 illustrates a cross section of a conventional prior art filter cartridge and housing for supporting a UV lamp assembly within the filter cartridge;

[0024]FIG. 3 illustrates a cross section view of a filter cartridge and housing incorporating the present invention;

[0025]FIG. 4 illustrates translation and bias of a filter cartridge in response to pressure differentials induced by a fluid to be filtered;

[0026]FIG. 5 illustrates axially stacked filter cartridges within a housing;

[0027]FIG. 6 is a plan view of a bottom end cap;

[0028]FIG. 7 is a cross sectional view taken along lines 7-7, as shown in FIG. 6;

[0029]FIG. 8 is a plan view of a top end cap; and

[0030]FIG. 9 is a cross sectional view taken along lines 9-9, as shown in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0031]FIG. 1 illustrates a conventional prior art filter cartridge 10 mounted within a representative housing 12. The filter cartridge includes a cylindrical filter element 14 having annular end caps 16, 18. Usually, these end caps are identical and each of the end caps is formed of a rubber-like resilient material. Housing 12 includes an inlet 30 for introducing a fluid to be filtered about the external surface of the filter cartridge. As represented by arrows 32, the fluid to be filtered flows through filter element 14 into an axial cavity 20 within the filter cartridge. The filtered fluid flows through the axial cavity 20, as represented by arrows 34, and through outlet 36, as represented by arrow 38. An annular knife edge 40 is formed on bottom 42 of housing 12 to compressively engage a corresponding surface of end cap 16. Upon such engagement, a seal is formed therebetween to prevent flow of unfiltered fluid from inlet 30 therebetween into axial cavity 20. A similar annular knife edge 44 extends downwardly from top 46 of housing 12 to compressively engage end cap 18. Upon such engagement, a seal is established to prevent flow past the end cap of unfiltered fluid into axial cavity 20. An annular space 48 is disposed about filter cartridge 10 and the corresponding wall of housing 12 to distribute the inflowing unfiltered fluid along the length of the external surface of the filter cartridge. Top 46 may be threadedly engaged with the rest of housing, 12, as illustrated. An O-ring 50, or the like, may be used to effect a seal between the top and the housing.

[0032] The integrity of the seal at each of end caps 16 and 18 is a function of the degree to which annular knife edges 40 and 44 compress the corresponding end cap. Initially, such seal is usually very effective. This seal depends upon several variables: the resiliency of the end caps to maintain compressive engagement with the corresponding annular knife edge, the resiliency of filter element 14 to bias the end caps against their respective annular knife edges, and, the properties of the fluid being filtered to induce deterioration of the resilience of the filter cartridge components.

[0033]FIG. 2 illustrates a filter cartridge 10 and housing 12 similar to that shown in FIG. 1 and representative of prior art embodiments. That is, it includes annular knife edges 40, 44 sealingly cooperating with annular end caps 16, 18. In some applications, an ultra-violet lamp is disposed within the filter cartridge to irradiate with ultra-violet radiation filtered fluid flowing into axial cavity 20. To protect the ultra-violet lamp, a sleeve 60 is disposed within axial cavity 20 in general radial alignment with filter cartridge 10. This sleeve houses the ultra-violet lamp and may be made of quartz or similar material transparent to ultra-violet radiation. An annular spacer 62, or the like, may be employed to maintain the displacement between sleeve and the filter cartridge. Necessarily, the sleeve is sealed by O-ring 64 or the like mounted in annular groove 66 in bottom 42 of housing 12. Usually, no support is provided between sleeve 60 and the interior surface of the filter cartridge. The outflow of the filtered fluid, as represented by arrows 68, occurs intermediate sleeve 60 and the adjacent surface of the filter cartridge.

[0034] Referring to FIG. 3, there is illustrated a filter cartridge 70 and housing 72 constructed in accordance with the present invention. The filter cartridge includes a filter element 74 of a hollow cylindrical shape and having a pair of annular end caps 76, 78; reference is also made to FIGS. 6, 7, 8 and 9 illustrating the end caps. End cap 76 includes a rim 80 for encircling the filter element, which rim extends from an annular flange 82. The flange may include ribs 84 or other projections for engaging the material of filter element 74 to retain the end cap in place. A circular sleeve 86 extends from annular flange 82 to define a cylindrical space therewithin. End cap 78 includes the same elements as end cap 76. However, the main difference between the two end caps is that circular sleeve 94 of end cap 78 is of greater diameter than that of circular sleeve 86 of end cap 76. Thereby, the amount of surface area of annular flange 82 radially external to circular sleeve 86 is less for end cap 78 than it is for end cap 76.

[0035] Housing 72 includes a cylinder 96 defining a compartment 98 for receiving filter cartridge 70. It also includes an inlet 100 for introducing fluid to be filtered. A circular in cross section support or stud 102 extends upwardly from bottom 104 of cylinder 96 to penetrably engage aperture 106 in annular flange 82. As shown in FIG. 3, the diameter of circular sleeve 86 of end cap 76 is greater than the diameter of stud 102. An O-ring 108 is disposed about stud 102. Circular sleeve 86 encircles and sealingly engages O-ring 108 to effect a seal between end cap 76 and stud 102. As shown in FIGS. 6 and 7, circular sleeve 86 may be segmented with segment 87 extending radially inwardly to retain O-ring 108 within the circular sleeve. By inspection, it will become evident that filter cartridge 70 may translate along its axis of rotation to some extent and O-ring 108 will accommodate such translation without compromising the seal between the circular sleeve and the stud. The extent of translation possible is, of course, a function of the width of circular sleeve 86, the height of stud 102 and the relative position of end cap 76 with the stud.

[0036] Top 110 is threadedly engaged with cylinder 96 by threads 112 to secure the top to the cylinder and retain filter cartridge 70 therebetween. The junction between the top and the cylinder is sealed by O-ring 114 to prevent leakage through the junction. Top 110 includes a circular stud 116 extending downwardly into the space defined by circular sleeve 94 of end cap 78. The diameter of stud 116 is less than the internal diameter of circular sleeve 94 to permit placement of an O-ring 118 therebetween and effect a seal. An outlet 120 is disposed in top 110 to accommodate outflow of filtered fluid, as represented by arrow 130.

[0037] A fluid to be filtered is introduce through filter 100 and flows into annular space 122 disposed between cylinder 96 and the external surface of filter element 74. The fluid to be filtered then flows through the filter element, as depicted by arrows 124. The filtered fluid entering axial space 126 flows toward outlet 120, as depicted by arrows 128 and through the outlet, as depicted by arrow 130.

[0038] To accommodate uses wherein an ultra-violet lamp is disposed within filter cartridge 70 to irradiate and kill microorganisms in the fluid flowing out of filter element 74 and to oxidize any organic matter that may be present, a positioning member 140 may be incorporated in end cap 78. The positioning member extends downwardly within cylindrical space 142 interior of filter element 74. It includes a circular shroud 144 that may support a plurality of radially inwardly extending ribs 146. These ribs, or the interior surface of the shroud, may be canted inwardly toward the upper end, as illustrated. An aperture 148 is centrally disposed within end cap 78 internal of the shroud to accommodate flow of the fluid through the shroud and into outlet 120.

[0039]FIG. 4 illustrates a filter cartridge 70 and housing 72 as shown in FIG. 3 with the addition of a sleeve 150 extending upwardly from bottom 104 of the housing. The sleeve is of ultra-violet transmissive materials, such as quartz. An ultra-violet lamp is mounted interior of the sleeve to irradiate the water flowing out of filter element 74 into annular space 152 intermediate the filter element and sleeve 150. The upper end of the sleeve is rounded, as illustrated, and nests within shroud 140 against ribs 146, which ribs help stabilize the sleeve within the housing. Circular sleeve 86 of end cap 76 extends about sleeve 150 in spaced relationship therewith to accommodate O-ring 108 placed therebetween to form an effective seal to prevent unfiltered fluid from entering annular space 152. Thus, sleeve 150 acts in the manner of a support for the filter cartridge. As discussed above, the area of annular flange 82 is Greater than the area of annular flange 90 of end cap 78. Even though the pressure of the unfiltered fluid acting upon each of annular flanges 82, 90 is essentially the same, the force acting upon end cap 76 is greater than the force acting upon end cap 78 due to the differences in area. Such greater force acting upon end cap 78 will urge filter cartridge 70 along sleeve 152 toward top 110, as depicted by arrows 154. This force positionally biases the filter cartridge toward top 110 and will result in maintaining the integrity of the seal provided by O-ring 118 intermediate circular sleeve 94 and stud 116. That is, the seal attendant top 110 is maintained both statically and dynamically.

[0040] Referring to FIG. 5, there is shown a further embodiment of the present invention wherein multiple filter cartridges are stacked end to end. Housing 160 is formed of cylinder 162 and top 164 secured to the cylinder in the manner described above. Cylinder 162 is of sufficient length to accommodate two or more filter cartridges. In the embodiment illustrated, two filtered cartridges (70A, 70B) are mounted end to end within housing 160. End cap 76 of lower filter cartridge 70A is mounted on stud 102 of bottom 104, as described above. Similarly, end cap 78 of the upper filter cartridge 70B is mounted upon stud 116 of top 164, as described above. End cap 78 at the upper end of lower filter cartridge 70A includes a circular sleeve 94 which is of greater diameter than circular sleeve 86 extending from end cap 76 located at the bottom of the upper filter cartridge 70B. The annular space between circular sleeves 86 and 94 is filled with an O-ring 166 to effect a seal therebetween. Thereby, the unfiltered fluid entering through inlet 100 is precluded from flowing into cylindrical space 168 within each of filter cartridges 70A, 70B. Flow through circular space 168 into outlet 120 is accommodated by aperture 148 in end cap 76 of lower filter cartridge 70A, aperture 106 in end cap 76 of upper filter cartridge 70B and aperture 148 in end cap 78 of the upper filter cartridge. As discussed above, any contraction or expansion of the filter elements of either or both of filter cartridges 70A, 70B after a period of use may result in axial displacement of the circular sleeves relative to one another or an circled stud. Since an intervening O-ring may roll or slide to accommodate such displacement, the sealing effect of the O-rings is not compromised.

[0041] While the invention has been described with reference to several particular embodiments thereof, those skilled in the art will be able to make the various modifications to the described embodiments of the invention without departing from the true spirit and scope of the invention. It is intended that all combinations of elements and steps which perform substantially the same function in substantially the same way to achieve the same result are within the scope of the invention. 

We claim:
 1. A filter apparatus said apparatus comprising in combination: a) a filter cartridge, said filter cartridge comprising: i) an hollow cylindrical filter element having opposed ends; ii) first and second end caps, one of said first and second end caps being mounted at each end of said filter element; and iii) each of said first and second end caps including a circular sleeve extending away from said filter element, an annular flange extending radially outwardly from said circular sleeve and an aperture disposed within said annular sleeve internal of said circular sleeve; b) a housing having an inlet and an outlet for retaining said filter cartridge to filter fluid flowing into said housing through said inlet and discharged through said outlet, said housing comprising: i) a bottom having a support extending therefrom for penetrable engagement with said aperture of said first end cap; ii) an O-ring disposed about said support in sealing engagement with said circular sleeve of said first end cap; iii) a top detachably attached to said housing for replacing said filter cartridge; iv) a stud extending from said top through said aperture of said second end cap and at least into the confines of said circular sleeve of said second end cap; and v) an O-ring disposed about said stud in sealing engagement with said circular sleeve of said second end cap.
 2. A filter apparatus as set forth in claim 1 wherein said support comprises a sleeve for containing an ultra-violet lamp to irradiate the interior surface of said filter cartridge and the fluid flowing therefrom.
 3. A filter apparatus as set forth in claim 1 wherein said circular sleeve of said second end cap is of greater diameter then the diameter of said circular sleeve of said first end cap.
 4. A filter apparatus as set forth in claim 3 including at least two of said filter cartridges mounted end to end within said housing, said circular sleeve of said second end cap of one of said filter cartridges being juxtaposed with said circular sleeve of said first end cap of another of said filter cartridges and an O-ring disposed intermediate said circular sleeves of said first and second end caps.
 5. A filter apparatus as set forth in claim 1 wherein the area of said annular flange of said first end cap radially outwardly of said circular sleeve is of greater area than the area of said annular flange of said second end cap radially outwardly of said circular sleeve, whereby, the pressure of the fluid flowing through said filter apparatus will urge said filter cartridge toward said top.
 6. A filter cartridge, said filter cartridge comprising in combination: a) a cylindrical filter element having opposed ends; b) a pair of end caps, one end cap of said pair of end caps being mounted at each end of said filter element; and c) each end cap of said pair of end caps including a circular sleeve extending away from said filter element, an annular flange extending radially outwardly from said circular sleeve and an aperture disposed within said annular flange and interior of said circular sleeve.
 7. A filter cartridge as set forth in claim 6 including a rim disposed at the perimeter of said annular flange of each of said pair of end caps juxtaposed with the external surface of said filter element.
 8. A filter cartridge as set forth in claim 7 including at least one projection extending from said annular flange of each end cap of said pair of end caps into penetrable engagement with the respective end of said filter element.
 9. A filter cartridge as set forth in claim 7 wherein said circular sleeve of one end cap of said pair of end caps is of greater diameter then the diameter of said circular sleeve of the other end cap of said pair of end caps.
 10. A filter cartridge as set forth in claim 6 wherein the diameter of said circular sleeve of one end cap of said pair of end caps is greater than the diameter of the said circular sleeve of the other end cap of said pair of end caps.
 11. A filter cartridge as set forth in claim 6 including an O-ring disposed within and supported by each of said circular sleeves.
 12. A filter cartridge as set forth in claim 6 including a positioning member extending from one end cap of said pair of end caps into the interior of said filter element for receiving an element to position said filter cartridge relative to such element.
 13. A filter cartridge as set forth in claim 12 wherein said positioning member circumscribes said aperture in said one end cap.
 14. A filter cartridge as set forth in claim 12 wherein said positioning member includes a plurality of ribs for engaging the element.
 15. A filter cartridge as set forth in claim 6 including a positioning member extending from one end cap of said pair of end caps and adapted to receive the closed end of a sleeve containing an ultra-violet lamp.
 16. A filter cartridge support, said filter cartridge support comprising in combination: a) a housing for retaining a hollow filter cartridge to filter a fluid flowing through said housing, said hollow cartridge including a pair of end caps with each end cap defining a circular sleeve; b) said housing including a cylinder for substantially enclosing said filter cartridge therein, said cylinder including a bottom; c) a support extending from said bottom for penetrable insertion through an aperture in one end cap of said pair of end caps of said filter cartridge and within said associated circular sleeve; d) first O-ring disposed about said support sealingly engaging said associated circular sleeve upon mounting of said filter cartridge within said housing; e) a top detachably attached to said cylinder for enclosing said filter cartridge in said housing; f) a stud extending from said top for insertion within said circular sleeve of the other end cap of said pair of end caps of said filter cartridge; g) a second O-ring disposed about said stud for sealingly engaging said associated circular sleeve upon mounting of said filter cartridge within said housing; h) an inlet for conveying a fluid to be filtered to the external surface of said filter cartridge; and i) an outlet for discharging the filtered fluid from the internal surface of said filter cartridge.
 17. A filter cartridge support as set forth in claim 16 wherein said support comprises a further stud.
 18. A filter cartridge support as set forth in claim 16 wherein said support comprises a sleeve for housing an ultra-violet lamp.
 19. A filter cartridge support as set forth in claim 16 including an O-ring disposed about said support for sealingly engaging said circular sleeve of the corresponding one of said end caps of said filter cartridge.
 20. A method for sealing a filter cartridge within a housing, said method comprising the steps of: a) mounting the filter cartridge upon a support within and at one end of the housing to penetrably engage an aperture in a first end cap of the filter cartridge with the support; b) sealing the first end cap with the support with an O-ring mounted upon the support and in sealing engagement with a circular sleeve extending from the first end cap along the support; c) further mounting the filter cartridge upon a stud within and at another end of the housing to penetrably engage an aperture in a second end cap of the filter cartridge with the stud; and d) further sealing the second end cap with the stud with an O-ring mounted upon the stud and in sealing engagement with a circular sleeve extending from the second end cap along the stud.
 21. A method for sealing as set forth in claim 20 including the step of locating two filter cartridges in axial alignment within the housing, said step of locating comprising the step of positioning an O-ring about the circular sleeve extending from an end cap of one of the filter cartridges and within an overlapping circular sleeve extending from an end cap of another of the filter cartridges, sealingly engaging the circular sleeve extending from the other end cap of the one filter cartridge with the support and further sealingly engaging the circular sleeve extending from the other end cap of the other filter cartridge with the stud.
 22. A method for sealing as set forth in claim 20 including the step of engaging a closed end sleeve for containing a UV lamp within the filter cartridge, said step of engaging including the step of engaging a positioning member extending from an end cap into the filter cartridge with the closed end of the closed end sleeve. 